Make those Baubles Glow!

Set 40338 - the LEGO Christmas Tree - is probably one of the most desirable and most sought after Gift-with-purchase sets ever.  The pre-Christmas timing was perfect, the model is gorgeous, and it seems the stocks were not huge so it was immediately in demand.

We got hold of one through the time honoured tradition of "paying through the nose". 

Actually it wasn't that bad - a kind person took pity on us and sold us one at a reasonable rate!

So here we have it.  A beautiful LEGO Christmas tree.  You turn the top section and the train down at the bottom spins around.  But it needs more.  Much, much more!

Breaking it Down

Let's take a look at how it works.

  • There's a base with a spinning train set.
  • There's a red horizontal support beam to hold the upper part of the tree
  • Six fixed layers of tree.  Five of these have big baubles and diamonds.  The top one just has diamonds and dog poos 1x1 studs with swirled tops.
  • A top layer with the pointy top and star attached.  This section turns to make the train spin.
  • Through the centre runs a cylinder of 2x2 Round Bricks with an axle in the middle for strength.  This connects the turning top to the turning train set.

Plan of Action

We need to light it up.  I mean, it's a Christmas tree.  It HAS to be lit up.

Looking at the design there is no easy way to run lights to all the baubles and keep that spinning top section.  I found that if you remove the central 2x2 Round Bricks there is enough space for the axle to turn, and also hide some expansion boards to power the lights.  But it's too tight, and will jam easily.

It's also still not possible to light up the star and the top level, as the wires will get tangled in no time if you turn the top.

Changing the Model

This is actually pretty easy.  You need 4 x Brown 1x1 Round Plates - the same kind used to separate all the levels of the tree. 

  • Pull the top off the tree. 
  • Remove the column of 2x2 round bricks.
  • Remove the axle running down the middle.
  • Remove the small gold curved tiles and the 4x4 Black Ring pieces.
  • Join the top of the tree back on using the brown 1x1 round plates in the same way as the other layers.

Voila - you have a fixed tree.

Motorising the Train

This is a bit of a luxury and we just wanted to try it.  

We used a few bits we had lying around - and the end result isn't perfect but it works.  We hope you can improve on it!

The motor is a LEGO Power Functions M Motor and it's stuck to the base board behind the tree.  

We learned a new trick - a standard Technic washer piece fits inside a small LEGO tire.  Who knew?  This was the basis to our design - let the soft rubber tire run underneath the train track and make it spin.  Here's how it looks.

We've used a 1x2 Brick with Hole and lifted it up by 1 plate using a 2x2 Blue Plate that came with the tree.  We also therefore had to lift the central 4x4 block with another handy plate from our spares.  And then the two side arches each got a 2x1 plate added to level it all off.

The tire was from one of the kids' sets and it's connected with an axle.

That's about it really - no magic involved.  Here's the video showing the workings.


Lighting the Tree

Now we have an empty core to the tree it's pretty easy to light it up.

We used the following parts:

  • 4 x White Micro Bit Lights (for the diamonds at the top)
  • 1 x 15cm White Bit Light (for the star at the top)
  • 9 x 15cm White Bit Lights (for the baubles)
  • 2 x 30cm White Bit Lights (to light up the train set)
  • 1 x Micro Expansion Board 
  • 1 x 12 Port Expansion Board (in the middle of the tree) 
  • 1 x 5cm Connecting Cable (to link the micro board to the 12 port board)
  • 1 x 30cm Connecting Cable (feeds out the back)
  • 1 x 6 Port Expansion Board (to connect to the power)
  • 1 x USB Cable

First we light up the train set.  To make wiring easier we use 30cm White Bit lights connected to the 6 port expansion board behind the tree. Either side of the red supporting platform are my favourite brick - a 2x2 inverted tile.  The set comes with these in red, but we swapped them for trans-clear and they're perfect for holding a bit light facing down.

Next fit the base layer of the tree.  Feed the two wires from the previous step up through the middle and to the rear - this keeps them clear from the train track.

For this layer we're just lighting up the front bauble. Take off the bauble and fit a 15cm White Bit Light between the gold stud and the bauble.

Then remove the green 2x3 plate and replace it on top of the wire, neatly concealing it.

Now fit this layer back onto the base of the tree and run the two 30cm bit light wires out to the rear.

Grab the 12 port expansion board and connect the 30cm Connecting Cable to the end port.  Place the board vertically in the hole and run the 30cm cable out the back along with the two Bit Light wires.

Finally connect the wire from that front bauble to the 12 port board and test it works!

The next few levels all follow the same pattern:

  • Take a layer of the tree
  • Move the two baubles to the front of the model (as you can't see the back anyway)
  • Fit a 15cm White Bit Light under each bauble, between the bauble and the stud.
  • Lift and replace the green plates as needed to hide the wires and bring them into the centre.
  • Lower the whole layer onto the tree model and press gently into place
  • Use tweezers (highly recommended!) to gently push the excess wiring down into the centre of the tree so they're out of sight.

Repeat this for each layer until all 9 baubles are lit up!  So that's one bauble on the base layer, and 4 layers with 2 baubles each.  Be creative with the positioning and the colours!

Now we're finally up to the top layer.  Take it apart carefully.


Next grab the Micro Bit Lights!  Now be careful with these as they're so small and are a bit more fragile than our normal lights as as a result.

Take the Micro Expansion Board and fit a 5cm connecting cable to one end.  Plug all four Micro Bit Lights in.  And then add the last 15cm White Bit Light to the end port.  

Plug the 5cm connecting cable into the end port on the 12 Port Expansion Board and check all the lights work.  Those micro ports need to be pushed firmly into the sockets to connect.

Now just like on previous levels - you'll need to remove some of the green surface plates, and then place the micro bit lights under the gems.  This is a bit more delicate as there's not much space under there!

Once done you can replace the green plates to neatly trap the micro bit light wires.

And for the grand finale - let's fit that last 15cm White Bit Light into the star.  This is pretty easy - bend the bit light at a 90 degree angle (with the LED facing up) and push gently up into the cone at the top of the tree.  Then carefully replace the block below to trap the wire.  I find this kind of thing easier if you hold the base and the wire together in one hand, then lower the top down.  This prevents trapping the cable badly.

Once done remove the side panel, run the wire down the side, and refit to conceal the wiring.

 Connect that bit light wire to a spare port on the 12 Port Expansion Board and carefully place the top section back onto the tree.  Again, use tweezers to carefully push the excess cables down into the centre of the tree.

Wiring Diagram

Here's a handy schematic showing the components and how they're connected together.  Remember the 12 port board and the micro expansion board are hidden inside the core of the tree.



The End Result

And here it is in all its glory.

And here's the video showing the lights and motor effect.  This was from an earlier version of the lighting so the baubles aren't quite so nicely spread around the model in this version.

Want to do it yourself?

We've put all the parts required for this project into a custom bundle, applied a generous discount, and added it to our site as a product.  You can choose a USB or battery pack version depending on which you prefer.

Find the parts here on our product page.

If you'd rather have a different combination of parts for a bigger or smaller build just let us know what you want!

Thanks for reading - drop us a line with requests or suggestions for our next project!

Elegant Bricks





Leave a comment

All comments are moderated before being published